Reporting of uterine fibroids on ultrasound examinations: an illustrated report template focused on surgical planning

Uterine fibroids are the most common benign gynecologic tumors in women of reproductive age, and ultrasound is the first-line imaging modality for their diagnosis and characterization. The International Federation of Gynecology and Obstetrics developed a system for describing and classifying uterine fibroids uniformly and consistently. An accurate description of fibroids in the ultrasound report is essential for planning surgical treatment and preventing complications. In this article, we review the ultrasound findings of fibroids, detailing the main points to be reported for preoperative evaluation. In addition, we propose a structured, illustrated report template to describe fibroids, based on the critical points for surgical planning.


INTRODUCTION
Uterine fibroids are the most common benign gynecological tumors in women of reproductive age (1,2) . Most women with fibroids are asymptomatic, and nearly a third of patients have significant symptoms such as dysmenorrhea, menorrhagia, abnormal uterine bleeding, secondary anemia, pelvic pain, and infertility (1,2) . The treatment of patients with uterine fibroids should be individualized on the basis of the symptoms, patient age, patient desire to preserve fertility or the uterus, and the characteristics of the nodules (e.g., size and location), as well as the availability of therapy and the experience of the attending physician (2,3) . In this context, ultrasound is considered the initial test of choice for the diagnosis of fibroids in symptomatic patients, mainly due to its broad availability, ease of use, cost-effectiveness, high sensitivity, and high specificity (4,5) . The examination should be performed by specially trained physicians, with the aim of accurately identifying and describing all fibroids (4,5) . Other aspects that are crucial in the choice of treatment-the size and location of fibroids; the presence and size of the submucosal component; penetration of the myometrial component; and with standardized language, could improve the communication of the results of ultrasound examinations and the confi dence of the gynecologist in those results (14) .
In the present study, we illustrate the main fi ndings to be reported in an ultrasound report of fi broids. We also propose a structured template for transvaginal ultrasound reports, designed to facilitate the preoperative evaluation of patients with uterine fi broids.

CLASSIFICATION OF FIBROIDS
Traditionally, the classifi cation of fi broids is based on their location in relation to two anatomical planes (15) : the endometrium and the uterine serosa. Thus, uterine fi broids are classifi ed as submucosal, intramural, or subserosal (16) . With advances in diagnostic modalities, the need arose for a detailed, universally accepted classifi cation system as a guide for choosing the most appropriate treatment (17) . Therefore, in 2011, the FIGO classifi cation system for causes of abnormal uterine bleeding was developed (17,18) . Currently, the FIGO classifi cation includes a total of nine types of fi broids (8) -types 0 through 8-as presented in Table 1 and Figure 1.
The FIGO classifi cation system was revised in 2018 (19) . The revised version suggests that an estimate of the total uterine volume should be provided in the ultrasound report, as should the estimated total number of fi broids. In addition, the report should include the estimated volumes of up to four fi broids and their locations, described as anterior, posterior, right, left, or fundus. Furthermore, the relationship between the endometrium and fi broids should be recorded in accordance with the FIGO classifi cation system (19) .

ULTRASOUND DIAGNOSIS OF UTERINE FIBROIDS
On ultrasound, a uterine fi broid is classically characterized as a solid, round, well-defi ned, hypoechoic, heterogeneous lesion within the myometrium, often showing acoustic shadowing at the edge of the lesion, with or without internal fan-shaped shadowing ( Figure 2). On color Doppler (Figure 3), the circumferential fl ow around the lesion is often visible (20) . In addition, Fleischer et al. (21) successfully used three-dimensional (3D) color Doppler to demonstrate that hypervascular fi broids show a greater reduction in size after uterine artery embolization than do isovascular and hypovascular fi broids. Those authors also found that, after the procedure, standard ultrasound showed decreased uterine size and echogenicity and color Doppler imaging showed a marked decrease in blood fl ow to the leiomyoma.
The 2015 MUSA consensus suggested using a systematic approach to assessing and reporting ultrasound fi ndings of the myometrium and associated fi broids (20,22) . The relevant parameters are presented in Table 2. Intramural fi broid in contact with the endometrium but not extending into the uterine cavity or serous surface Intramural fi broid without contact with the endometrium and without extension into the uterine cavity or serous surface Subserosal fi broid with intramural extension > 50% and < 50% subserosal Subserosal fi broid with intramural extension < 50% and > 50% subserosal Subserosal pedunculated fi broid Other types of fi broids (e.g., cervical, broad ligament, and parasitic fi broids) Hybrid classifi cation used when a fi broid extends from the endometrial cavity to the serosa, composed of two numbers, separated by a hyphen, the fi rst characterizing the relationship between the fi broid and the endometrium and the second characterizing its relationship with the serosa  . FIGO classifi cation of fi broids: 0 = pedunculated intracavitary fi broid; 1 = submucosal fi broid that is < 50% intramural; 2 = submucosal fi broid that is ≥ 50% intramural; 3 = fi broid that is 100% intramural but in contact with the endometrium; 4 = intramural fi broid; 5 = subserosal fi broid that is ≥ 50% intramural; 6 = subserosal fi broid that is < 50% intramural; 7 = subserosal pedunculated fi broid; 8 = other (e.g., cervical and parasitic) fi broids; and 2-5 = hybrid fi broid that is < 50% submucosal and < 50% subserosal.

KEY POINTS FOR THE SURGICAL TREATMENT OF FIBROIDS
Decisions regarding the treatment of fi broids should take into consideration the presence of symptoms (often pain, bleeding, or infertility); the age and reproductive aspirations of the woman; and the number, size, and location of the fi broids. Most asymptomatic patients do not need specifi c treatment, requiring only periodic monitoring with imaging examinations (22,23) . Although the initial treatment for most patients with symptoms of abnormal bleeding is clinical, the defi nitive treatment for fi broids is surgical (23) . Typically, hysterectomy and myomectomy are the most effective treatments (24) . Alternatives to surgery include embolization of the uterine arteries and magnetic resonance imaging (MRI)-guided focused ultrasound ablation (25) . The key imaging aspects for the surgical treatment of fi broids are outlined in the following items.

Uterine volume
It is recommended that the longitudinal, anteroposterior, and transverse diameters of the uterus be measured, because that provides the uterine volume in cm 3 , as shown in Figure 4, which is extremely useful in the surgical planning (26,27) . When the uterine volume exceeds 375 mL, the effi ciency of transvaginal ultrasound in fi broid mapping is signifi cantly lower than is that of MRI (28) .

Number of fi broids
The number of fi broids will determine whether fi broid resection is feasible for symptom control. When there are numerous fi broids, radiologists should consider reporting a range of 10-20. Although it is not necessary to describe all lesions, a minimum number should be chosen (27) . Most previous studies have suggested that radiologists should describe no more than four non-submucosal fi broids and should describe all submucosal fi broids (25)(26)(27) , as depicted in Figure 5.

Size -Three perpendicular diameters
Outer lesion-free margin -Distance from the serosal surface Inner lesion-free margin -Distance from the endometrial surface Echogenicity -Hypoechoic, isoechoic, or hyperechoic

Size
It is recommended that each fi broid described in the report be systematically measured in three orthogonal planes, to obtain its volume in cm 3 , as illustrated in Figure  6. Knowledge of the size of each fi broid helps the gynecologist estimate the probability that the fi broids are (collectively) the direct cause of the symptoms and determine the best surgical approach in each case (28) .

Location
It is essential to register the location of each fi broid as being in the wall of the uterus-anterior, posterior, or lateral (right or left)-in the uterine fundus, or global ( Figure  7). For example, when the fi broid is located in the lateral wall or in the uterine fundus, there is a greater degree of complexity in the hysteroscopic surgical procedure (29) . myomectomy, or hysterectomy if there is no possibility of or desire for pregnancy. Accurately differentiating FIGO 2 fi broids from FIGO 3 and 4 fi broids is critical, because the surgical approach differs (32) : FIGO 2 fi broids are resected by hysteroscopy; and FIGO 3 and 4 fi broids are resected by video-assisted laparoscopy or laparotomy. Figure  9 shows an intramural FIGO 4 fi broid.

FIGO classifi cation
Submucosal (FIGO 0, 1, and 2) uterine fi broids constitute a common cause of menorrhagia and dysmenorrhea because they project into the endometrial cavity. For women who wish to become pregnant, submucosal fi broids are especially worrisome because they can cause infertility or miscarriage (30) . Therefore, such fi broids require surgical treatment, regardless of size. Treatment often includes hysteroscopic resection. For symptomatic patients who have no desire to become pregnant, hysterectomy can be an option. Hysteroscopic myomectomy of a bulky FIGO 2 fi broid, as depicted in Figure 8, can be diffi cult and might require a two-stage surgical procedure or uterine artery embolization (31) .
Fibroids without a submucosal component (intramural and subserosal fi broids) that cause symptoms of mass effect in the uterine cavity or adjacent structures such as the bladder and bowel can be treated with embolization,  Treatment of bulky symptomatic fi broids and of bulky subserosal (FIGO 5, 6, and 7) fi broids in adjacent structures includes embolization, video-assisted laparoscopic myomectomy, and laparotomy. Due to their vascular pedicle, FIGO 7 fi broids are also at risk of twisting, shedding, or becoming parasitized in the pelvis. For FIGO 5, 6, and 7 fi broids, the treatment options include embolization, laparoscopic resection, laparotomy or hysterectomy (33) . Figure  10 shows a FIGO 6 fi broid in the uterine fundus.
A FIGO 2-5 fi broid, which is less than 50% submucosal and less than 50% subserosal (Figure 11), is a commonly found hybrid type of fi broid. Due to the size and extent of such a fi broid, treatment includes targeted therapy such as MRI-guided focused ultrasound or embolization, although hysterectomy can be required if the fi broid is extensive (34,35) .

Myometrial mantle
The thickness of the myometrial mantle can be measured on transvaginal ultrasound ( Figure 12). Various authors consider the outer myometrial mantle (distance from the fi broid margin to the serous surface) and the inner myometrial mantle (distance from the fi broid margin to the endometrial surface) to be key factors for hysteroscopic resection of submucosal fi broids. Some studies suggest that, in FIGO 2 fi broids, there is a greater chance of uterine rupture during resection if the outer myometrial mantle is smaller than 0.5 cm (36) .

Adenomyosis
Recognition of adenomyosis is critical because it can change the treatment approach, patient counseling, and expectations. Adenomyosis, as shown in Figure 13, is defi ned as diffuse or focal invasion of the endometrial basal layer into the myometrium, can cause fi broid-like symptoms, and is identifi ed on ultrasound as thickening or irregularity of the junctional zone, asymmetry of the myometrial walls, acoustic bands in the myometrium (myometrial stratifi cation into fan-shaped shadowing), subendometrial/myometrial echogenic linear striations, myometrial cysts, and increased vascularization on Doppler, with penetrating vessels in the affected area (37) .

Endometriosis
A preoperative diagnosis of endometriosis directly infl uences the planning of the surgical treatment of fi broids and the composition of the multidisciplinary surgical team. Therefore, screening for endometriosis on routine transvaginal ultrasound, based on the International Deep Endometriosis Analysis group consensus (38) , should be encouraged and should be performed with a practical, dynamic, four-step ultrasound approach: routine evaluation of the uterus and adnexa with special attention to ultrasound signs of adenomyosis and the presence or absence of endometriomas ( Figure 14); evaluation of indirect soft markers, such as site-specifi c sensitivity and ovarian mobility; assessment of the pouch of Douglas status by realtime ultrasound testing for the "sliding sign"; and identifi cation of deep infi ltrating endometriotic nodules in the anterior and posterior compartments, which necessitates evaluation of the bladder, vaginal vault, retrocervical region, uterosacral ligaments, and bowel.

SALINE INFUSION ULTRASOUND AND 3D ULTRASOUND FOR PREOPERATIVE EVALUATION OF FIBROIDS
Sonohysterography consists of transvaginal ultrasound combined with the infusion of sterile saline through a catheter into the uterine cavity. This minimally invasive 3D technique allows clear delineation of the uterine cavity. It is superior to two-dimensional ultrasound for the diagnosis of intrauterine abnormalities such as polyps and submucosal fi broids. In a pooled analysis using the gold standard (hysteroscopy) as the reference (39) , saline infusion ultrasound was found to have a sensitivity of 92% and a specifi city of 90%, compared with 64% and 90%, respectively, for transvaginal ultrasound. Finally, 3D ultrasound can facilitate the spatial assessment, allowing more accurate characterization and localization of fi broids than what is achieved with two-dimensional ultrasound. Multiplanar views, especially the coronal view, have improved the description of fi broids on ultrasound (40) .

PROPOSAL FOR A STRUCTURED ULTRASOUND REPORT TEMPLATE FOCUSING ON THE PREOPERATIVE EVALUATION OF PATIENTS WITH FIBROIDS
Although the FIGO classifi cation system has provided gynecologists with a well-standardized framework for characterizing uterine fi broids, there is still signifi cant variability across transvaginal ultrasound reports in terms of the quality of the descriptions of fi broids. Incomplete descriptions of fi broids or associated lesions such as adenomyosis and endometriosis can raise questions or lead to inappropriate surgical planning (40) . Consequently, a structured, illustrated model of an ultrasound report, standardizing the description of uterine fi broids-based on the critical criteria for surgical management, the FIGO classifi cation of uterine fi broid location, and the MUSA group descriptors-could be useful for sonographers and physician examiners. A structured, accurately illustrated ultrasound report of fi broids allows gynecologists to choose the best treatment for the patient, be it hysteroscopy, laparoscopy, laparotomy, or embolization (41,42) . The proposed report template is shown in the Appendix. In addition, bowel preparation can be added if specifi cally requested by the attending physician. Another relevant topic when considering the imaging evaluation of patients with fi broids is illustrating the imaging fi ndings with drawings or sketches (Figure 15), which is also strongly recommended and valued by surgeons and patients because it provides a roadmap for treatment (43)(44)(45) .

Report of painful sensitivity on mobilization with a transducer
Yes ( ) No ( ) Anterior pelvic compartment Bladder: good repletion; thin, regular walls; and homogeneous anechoic content. There was no evidence of endometriotic lesions in the bladder. In the search for adhesions, there was mobility and anatomical sliding of the bladder wall against the anterior wall of the uterus (positive sliding sign).

Posterior pelvic compartment
There is no evidence of endometriotic foci in the retrocervical region and uterosacral ligaments. There are no evident signs of thickening or nodules in the intestinal loops or rectum detectable without bowel preparation. Signs of adenomyosis ( ) Absent ( ) Focal ( ) Diffuse

CONCLUSION
There are key points in the characterization of fibroids that help gynecologists plan the surgical treatment and have the potential to allow complications and treatment failure to be avoided. The structured, illustrated ultrasound report model proposed here, which is based on those critical points, could improve patient counseling and treatment planning, as well as facilitating the selection of the most appropriate medical or surgical treatment strategy.